The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a semiconductor structure including a deep trench capacitor having a high capacity and located in a bulk silicon substrate as well as a method of forming the same.
In the semiconductor industry, deep trenches, which typical have a depth exceeding 1 micron (μm), are employed to provide a variety of useful devices including a deep trench capacitor. The deep trenches may be utilized in a stand-alone semiconductor circuit such as, for example, a dynamic random access memory (DRAM) circuit to provide deep trench capacitors, or the deep trenches may be utilized as an embedded circuit component of a semiconductor chip that also includes other semiconductor circuits such as a processor core or other logic circuits. Particularly, embedded deep trench capacitors may be used to enable an embedded memory device, for example, an embedded dynamic random access memory (eDRAM) cell, a passive component of a radio frequency (RF) circuit, or a decoupling capacitor that provides a stable voltage supply in a semiconductor circuit.
Typically, deep trench capacitors are formed into a semiconductor handle substrate of a semiconductor-on-insulator (SOI) substrates; the semiconductor handle substrate is located beneath a buried insulator layer and an active semiconductor device layer of the SOI substrate. SOI substrates have been employed in the semiconductor industry for performance benefits do to reduced capacitive coupling between semiconductor devices and the semiconductor handle substrate.
Despite the benefits that SOI substrates provide in eDRAM manufacturing, there is an ongoing desire to replace SOI substrates with bulk semiconductor substrates since bulk semiconductor substrates are cheaper and are more readily available. Notably, there is a need for providing a deep trench capacitor that has a high capacity and that is formed in a bulk semiconductor substrate.